1 . Field of the Invention
The present invention relates generally to cabinets for housing electrical components and, more specifically, to cabinets equipped with cooling systems for removing internally generated heat.
2. Description of the Related Art
Customized cabinets for housing electrical components, such as telecommunications loop electronics equipment, are typically constructed by assembling parts made of sheet aluminum. One type of cabinet, known as a remote terminal cabinet, is mounted outdoors on a concrete pad and must be essentially sealed to keep out water. Concomitantly, the components housed in the cabinet produce heat in operation, thus necessitating a cooling system capable of removing heat from within the sealed cabinet. The dual requirements of sealing to protect interior components and cooling to remove heat generated by the interior components are difficult to reconcile since most existing cooling systems require penetration into the interior chamber of a cabinet, thus providing potential access for water.
An additional problem associated with known cooling systems is that most are provided as "add-on" features and thus do not integrate well with the rest of the cabinet to provide optimum cooling performance. Moreover, most require modifications to the cabinet in the form of access holes for a cooling air flow generated by cooling fans. The fans themselves tend to be difficult to service due to the fact that the add-on units tend to be as compact as possible.
A known add-on cooling unit is described with reference to FIG. 1, wherein the unit is generally referred to by the numeral 20. The unit 20 is connectable to a cabinet 22 by boring attachment holes 24 in the top surface 26 of the cabinet 22. Vents 28 and 30 are cut into the top surface 26 of the cabinet 22 to provide a vertical air flow as indicated by the directional arrows. Fans 30 force the air flow in one side of a unit, then downwardly into the cabinet 22 thereby forcing hot air upwardly as indicated by the directional arrow. The hot air passes over a cooling fin assembly 32 before being blown out of the unit 20. The cooling fin assembly 32 includes a coil which contains a cooling liquid.
The unit described with reference to FIG. 1 typifies the problems associated with the known cooling systems. One problem is that by locating the unit on top of the cabinet, an outdoor use is not practical since the unit tends to be unsheltered and can allow water to leak into the vents 28 and 30 and through the attachment holes 24. Also, the fans 30 will be exposed to the elements and will thus have a propensity towards water damage.
In the known systems, such as what is illustrated in FIG. 1, the fans 30 tend to be unaccessible for maintenance except by removing the entire unit. Thus, maintenance is impractical.
Finally, cooling units such as what is illustrated in FIG. 1 having a vertically oriented air flow tend to be less efficient coolers since the incoming and outgoing air currents are located in one portion of the cabinet and thereby provide uneven cooling.